import java.sql.*;

public class Main {
    public static void main(String[] args) {
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        //jdbc 步骤
        //1.0加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8&useSSL=false&serverTimezone=UTC";
             connection = DriverManager.getConnection(url, "root", "121628");
//            if(connection !=null){
//                System.out.println("连接成功");
//            }
        //3.写sql
        String sql = "select * from user";
        //4.预编译sql
             preparedStatement = connection.prepareStatement(sql);
        //5.执行sql
             resultSet = preparedStatement.executeQuery();
        //6.遍历结果
        while (resultSet.next()) {
            int id = resultSet.getInt(1);
            String name = resultSet.getString(2);
            String pass = resultSet.getString(3);
            System.out.println(id + " " + name + " " + pass);
        }
        //7.关闭资源
        resultSet.close();
        preparedStatement.close();
        connection.close();


        }catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //7.关闭资源
            try {
                if(resultSet != null) {
                    resultSet.close();
                }
                if(preparedStatement != null) {
                    preparedStatement.close();
                }
                if(connection != null) {
                    connection.close();
                }

            } catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }
    }
}